Although men who have sex with men (MSM) are at very high risk for HIV globally, this group has only recently become an important focus of national HIV/AIDS programs in sub-Saharan Africa. While it is clear that antiretroviral therapy (ART) can reduce AIDS-related morbidity and mortality and prevent sexual transmission from HIV-infected MSM, little is known about antiretroviral adherence and barriers to care among African MSM. We have worked with MSM involved in sex work on the Kenyan coast since 2005, and have found significant disparities in HIV treatment engagement, ART adherence, and clinical outcomes in this group, due at least in part to stigma and social isolation. Involving bot providers and peers in an intervention to support MSM as they initiate ART, combined with regular messaging to promote adherence, is an innovative strategy to address this treatment gap. In this R34 application, prepared in response to PAR-11-278 Discovery, Development, and Testing of Novel Interventions to Advance HIV Prevention and Care, we propose a 3-year developmental project to design and pilot test a culturally appropriate and generalizable antiretroviral adherence intervention for African MSM. The project is a multidisciplinary collaboration among experienced investigators at the University of Washington, Kenya Medical Research Institute, University of Oxford, and Brown University, based on a foundation of 7 years' experience conducting research with Kenyan MSM that underpins the significance and innovation of this proposal. Our specific aims are to: (1) conduct qualitative research including in-depth interviews and focus groups with HIV-1-seropositive MSM, treatment-experienced peers, and their providers to identify common barriers and likely facilitators of ART adherence; (2) design and field test a theoretically driven intervention for MSM combining provider and peer support to encourage engagement in care, build trust, and deliver regular adherence messaging; and (3) implement a pilot randomized controlled trial (RCT) of the resulting multi-component intervention versus standard care with 60 MSM participants. We will develop training modules and supporting materials for an intervention including patient-centered care, motivational interviewing, peer support, and adherence messaging adapted to the specific findings of our qualitative study. The proposed research is consistent with and responds to priorities set by the NIH Office of AIDS Research on reducing HIV-related disparities and improving disease outcomes for HIV-infected individuals, and is also consistent with the recommendation set forth in the 2011 Institute of Medicine report on The Health of Lesbian, Gay, Bisexual, and Transgender People to implement a research agenda designed to advance knowledge and understanding of LGBT health. Findings from this formative R34 study will provide data on the feasibility, acceptability, tolerability, safety, and preliminary effect sizes or an R01 proposal to test this intervention and its components in a fully powered RCT including a larger, more diverse sample of MSM from multiple sites in sub-Saharan Africa.